Monolayer exchange chemistry of γ-Fe2O3 nanoparticles

Monolayer modification of alkylamine-protected gamma-Fe2O3 nanoparticles using functionalized alcohols and diols is presented. the stability of the modified nanoparticles was found to be dependent on the nature of the introduced alcohol: both bidentate surface-ligand bonding and steric blocking by bulky tail groups were necessary to produce systems resistant to agglomeration. EPR, UV-vis, and powder XRD analyses of the pre- and post-modified nanoparticles demonstrated that the core gamma-Fe2O3 functionality was unaffected by the change in monolayer composition. Finally, multiple ligands could be readily incorporated into the monolayer using a simultaneous displacement reaction.